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lydiakitty

lead in soil

lydiakitty
16 years ago

Hi,

I may take a plot in a community garden this spring, which I would use to grow vegetables. I'm in a urban environment, so pollution is a concern. The most recent testing of the soil in this garden shows a level of lead of 80 parts per million. I'm interested in know what people in this forum think - would the veggies grown be safe to eat? Would you serve such vegetables to your family?

I have done some research regarding lead levels...supposedly it occurs naturally in the soil up to about 40 parts per million, and the "dangerous" (it's unclear what that actually means)level is 200 parts per million. I've also read that root vegetables and leafy greens absorb the most lead, and that the main danger from lead contaminated soil is actually the soil itself, and not food grown in it. What do you think?

Thanks everyone!

Comments (19)

  • len511
    16 years ago

    Supposedly lead interferes with chlorophyll production, how much i don't know. I think the important question would be how much lead could be absorbed into the plant before it made it unattractive for human consumption, and would that be enough to present any danger.

  • nc_crn
    16 years ago

    Sadly, 200 ppm isn't really uncommon.

    You should avoid huge plantings of root veggies, yes. Shoot veggies (asparagus/rhubarb/etc) tend to take up a little bit more, but not a huge amount more. You're looking at 10% or less (of the ppm) being uptaken by the fruiting veggies (peppers, tomatoes, etc).

    Even though it's probably safe (400ppm is what's allowed on children's playground equipment, for reference) you may want to keep small children from eating a lot of...wait, what am i saying? that shouldn't be a problem. heheh.

    Seriously, though...given current knowledge...what you got going on is considered mostly safe though you might not wanna grow asparagus or carrots there if you plan on eating a lot of them in your diet.

    There is some debate on the low-growing leafy greens, though...I don't know enough about that to say anything.

  • nc_crn
    16 years ago

    "10% or less (of the ppm) being uptaken by the fruiting veggies"

    I should say that by 10% or less studies tend to show its closer to 0-5% than 5-10% of the original percentage of ppm.

  • nc_crn
    16 years ago

    "I think the important question would be how much lead could be absorbed into the plant before it made it unattractive for human consumption, and would that be enough to present any danger."

    You're in a lot more danger not washing your produce more than how much the plants take up.

    Most exposure is going to happen where the soil/dust comes in contact with the produce. Root crop lead ppm can be cut severely just by peeling the root before eating it. There is some uptake directly by the plant, but most of the unsafe lead levels in veggies comes from a lack of washing them well more than the lead being incorporated into the plant's tissues.

  • nc_crn
    16 years ago

    Here's a study of lead uptake in plants. On page 4-6 there's charts of results of their studies. They studied some VERY high lead soils.

    www.bridges4kids.org/lead/binnspaper2003.pdf

  • justaguy2
    16 years ago

    nc-crn gives a good link. I always appreciate the studies on topics like this.

    80ppm in the soil isn't worth worrying about it would seem.

  • booberry85
    16 years ago

    I'm an environmental consultant that deals with lead-based paint issues on a daily basis. The Environmental Protection Agency (EPA) reference levels for lead in soils is not exceed 400 ppm in bare (i.e. no grass or gravel covered) soils in high contact areas (gardens, children's play areas, pet runs, etc), and below 1200 ppm in other parts of the yard where bare soil exists.

    Below is the link to part of the EPA regulation. The part regarding soil is on the second page, first column, about half way down under (c).

    Here is a link that might be useful: EPA 40 CFR 745.65(c)

  • lydiakitty
    Original Author
    16 years ago

    Thanks to everyone for the information...the link from nc-crn was especially helpful. I definitely will follow the recommendations everyone has given, and feel reassured that the food I'm growing is safe.
    Thanks again!

  • granite
    16 years ago

    Compost helps to detox your soil, so if you're worried about the levels of harmful stuff in your soil just compost there for 60 days or more and then garden with the area.

    Many plants detox the soil, Sunflowers and Indian Mustard are two of the most popular choices.

    Check out the document at this link (can't direct link it for some reason):

    [DOC]
    BROWN PATCH:
    File Format: Microsoft Word - View as HTML
    Sunflowers (Helianthus sp.) have the ability to remove radioactive and toxic metals from soil and water. Some strains of sunflowers can remove up to 95% of ...
    www.natureswayresources.com/DocsPdfs/bioremediation.doc

  • daleyc
    15 years ago

    is there a way of testing the soil to see how much lead there is?

  • booberry85
    15 years ago

    Below is a list of accredited laboratories. A soil sample should cost around $25.00 to analyze. You will find a shocking amount of difference in price. The laboratory should supply you with the container & paperwork (called a chain of custody) to fill out regarding the sample(s). The lab can also give you some general guidelines on taking the sample.

    Here is a link that might be useful: Environmental Lead Lab Approval Program

  • nc_crn
    15 years ago

    UMass provides soil testing for lead in your area.

    http://www.umass.edu/plsoils/soiltest/services1.htm

    It's usually not a big deal unless you're in an area with previous manufacturing/fabrication or near buildings where lead paint has peeled or been scraped off, though.

  • Scott
    5 years ago

    I know this is an old thread but I tried to access the list of places to test for contamination. I couldn’t get the search to work. Anyone have a resource? Thanks.

  • gardengal48 (PNW Z8/9)
    5 years ago

    Most professional soil testing labs will test for common contaminates, including lead, if requested. This is generally not a part of a typical soil test so an additional, specified service. Your local extension service office should be able to direct you to a local lab if they do not provide the service themselves.

    This link may help: Lead in Residential Soils. Also, UMass has an excellent reputation with their testing services and will test soils from just about anywhere (do not have to be local). The test you would request there is Total Sorbed Metals @ $55 per sample.

  • rhizo_1 (North AL) zone 7
    5 years ago

    Plants are used, and have been for generations, in the phytoremediation of heavy metals in soils. Plants take up these metals (including lead), store them in their tissues, effectively removing them from the soil but making the plants unsafe to eat if there are high levels of these metals.


    Phytoremediation of heavy metals

  • Scott
    5 years ago

    Would raised beds solve the problem? Like square foot gardening? Or would the roots still reach the soil?

  • daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa)
    5 years ago
    last modified: 5 years ago

    Just out of curiosity, do you have some reason to believe that your soil is contaminated with lead? Chemical dump sites can have all kinds of bad stuff in them. Not just lead. Roadside beds, especially with alkaline soil, are almost always contaminated with lead, because of the lead that used to be added to gasoline, though not usually at levels that are considered hazardous.

    You might get in touch with your local city resource recovery office. They might do the test for free. Around here, they do (for both lead and arsenic and, while they're at it, major plant nutrients). Whyever should they do this for free? I suspect that they're looking for seriously polluted sites, and lots of federal money is available for remediation if they find any. Offering tests for plant nutrients gives them hundred of samples from interested gardeners, who are also interested in possible contaminants.

  • Scott
    5 years ago

    I’m moving into an older neighborhood with small lots and houses very close together. Most are wood siding houses that were built in 1930s. I’d imagine that a lot of paint chips fell and blew around. I have young kids and another on the way. I want To make sure that the food I’m serving my family is healthy.


    I would love to have every square inch of my backyard into a veggie garden with raised beds. I’m worried about having beds close to the houses and garages.


    ps- we don’t have a house yet but we are actively looking.